A diving suit is one type of an underwater suit. Wetsuits and drysuits have been conventionally known as this type of diving suit. The major difference between a wetsuit and a drysuit is that the drysuit has a flexible waterproof zipper (also referred to as “water guard”) in, for example, a body covering/uncovering opening part of the suit.
A diving drysuit takes safety measures by preventing any damage or problems of the waterproof zipper, air supply valve and air exhaust valve.
Normally, the waterproof zipper has elements along inner rims (facing each other) of two strips of elastic, waterproof tape. The waterproof zipper is structured to open/close the watertight (also referred to as “airtight”) engagement between the elements by means of the strips of tape. The right and left strips of tape are opened widely in an oblique direction and strongly pulled, when both of the strips of tape are moved to forcibly open/close the waterproof zipper. Forcibly opening/closing the waterproof zipper often causes problems in the waterproof zipper such as weakening the engagement between the elements and consequently reducing the air-tightness therebetween or damaging the zipper itself as a slider comes off of the elements.
Therefore, when a person wears, by himself/herself, a conventional normal diving suit that has a waterproof zipper for opening/closing the body covering/uncovering opening part on the back of the diving drysuit, he/she needs to carefully wear or take off the suit so that the waterproof zipper does not break. This makes it significantly difficult to open/close the waterproof zipper.
There are proposed a variety of technologies on the placement of the waterproof zipper in order to form a covering/uncovering opening part of a diving suit (see Patent Documents 1, 2 and 3, for example).
Patent Document 1 discloses a diving suit that is provided with a covering/uncovering waterproof zipper passing through the back face of the main body of the diving suit from one of the shoulder surfaces to the other.
Patent Document 2 discloses a diving suit that is provided with a zipper which extends diagonally from a shoulder to the waist across the forward portion of the covering/uncovering upper torso portion.
Patent Document 3 discloses a diving suit in which a covering/uncovering waterproof zipper is disposed horizontally a back upper part so as to reach an upper part of either arm part.    Patent Document 1: Japanese Patent Application Publication No. H11-310193    Patent Document 2: Japanese Translation of PCT Application No. 2000-510413    Patent Document 3: Unexamined Utility Model Application Publication No. H6-23897
In the diving suits disclosed in Patent Documents 1 and 3, substantially part or the whole of the covering/uncovering waterproof zipper is placed on the back, which makes it difficult for a wearer to operate the zipper when wearing the diving suits by himself/herself. Thus, the wearer needs to have somebody open/close the waterproof zipper in order to wear or take off the diving suits smoothly.
The diving suit disclosed in Patent Document 1 claims that one can wear or take off the diving suit by himself/herself, but it is still difficult to smoothly open/close the waterproof zipper on the back of the neck of the diving suit.
In the case of the diving suit disclosed in Patent Document 2, the wearer can wear or take off the diving suit by himself/herself, due to the location of the covering/uncovering waterproof zipper. However, if the diving suit is a drysuit when the wearer stands up nearly straight in this diving suit, the pressure of the air remaining in the diving suit (the pressure here is referred to as “internal pressure” hereinafter) is normally approximately −0.8 atmospheres in each leg part, and the internal pressure in the chest part, especially the upper chest part, is as high as approximately 1.2 to 1.3 atmospheres. As a result, the waterproof zipper 10 partially swells up at the upper chest part due to the local high internal pressure, as shown in FIG. 1(A) (indicated by a reference numeral 10a in the diagram), causing a deformation or unevenness. When the wearer dives into the water or bends over under the water in this diving suit with such swelling of the waterproof zipper, the internal pressure concentrates on the swollen part and increases drastically, and, as a result, causes air-tightness between the elements, by worsening the engagement cracks in the waterproof zipper, generates a pinhole, and causes rupturing breakage (also referred to as “breakage”) of the zipper itself (indicated by a reference numeral 10b in the diagram).
In the case of a conventional waterproof zipper, if an external force forcibly acts on the waterproof zipper to open up both tapes of the waterproof zipper at the maximum open angle or more when wearing or taking off the diving drysuit, a slight difference in degree of stretching is generated between the tapes, thereby deteriorating the engagement between the elements, removing the elements from the slider of the waterproof zipper, and causing other damage to the waterproof zipper. For this reason, the wearer cannot wear the drysuit.
As described above, the problem in the conventionally known diving drysuit is that it does not have adequate countermeasures to not only the safety of the waterproof zipper but also the occurrence of problems and damage in the waterproof zipper.
For the purpose of solving the problems described above, the inventor of the present application came up with the following points as a result of keen investigations.
(1) A waterproof zipper, used for wearing or taking off a drysuit, is disposed in a chest part, or particularly in an upper chest part, in a chest width direction, so that a wearer can easily open/close the waterproof zipper on the chest without having a help of somebody.(2) Another zipper is provided on a front fabric (also referred to as “outer zipper”) to cover the upper side of the waterproof zipper (also referred to as “inner waterproof zipper”). The placement relationship between the waterproof zipper and the outer zipper is set in order to prevent swelling of the inner waterproof zipper as much as possible by pressing from the top, that is, from the outside, the inner waterproof zipper located under the outer zipper, by means of a combination of the front fabric, tensioned as a result of closing the outer zipper, and the outer zipper. This can prevent breakage of the waterproof zipper caused by local swelling thereof.(3) In addition, when a slider of the inner waterproof zipper is moved and stopped at a position of a lower end (also referred to as “slider end part”) (referred to as “lower end position” hereinafter), which is a largest opening position, both tapes of the inner waterproof zipper are prevented from opening up at the maximum open angle or more, so that a strong pull force does not act on the tapes. In order to do so, an area facing the lower end and the slider at the lower end position may be provided with means for preventing the tapes from opening up at an excessively large open angle from the slider that is stopped at the lower end position.